Back rest for a chair



FIG. 1 is a perspective view showing the top, left side and front of aback rest for a chair which forms my new design, the broken lines ofother parts of the chair in this and other figures being forillustrative purposes only and forming no part of my design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof; and,

FIG. 5 is a top plan view thereof.

The ornamental design for a back rest for a chair, as shown anddescribed.